Air and steam feeding device for furnaces



(No Model.) Y n 2 sheets-sheen 1. T. MURPHY. AIR AND STEAM FEBDING" DBVIB FOR FURNAGES.

l Patented Oct. 8, 1895'.

ANDREW BLRANAMA PHUTD-LITNO-WASHINGTUN, D C.

(No Model.) 2 sheets-sheen 2.

T.MURPHY. AIR AND STEAM FBEDING DEVICE FOR PURNAGBS. No. 547,670. Patented oct. 8, 1895 T /mi *El* v.

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THOMAS MURPHY, OF DETROIT, MICHIGAN.

Ala ANDSTEAMFEEDI'NG lolivier: FOR FURNACES.

SPECIFICATIONforming part of Letters Patent No. 547,670, dated October 8, 1895. Applications@ January 14, 1895. sean No. 534.89% @To model.)

To a/ZZ whom it may concern:

Be it known that I, THOMAS MURPHY, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michi` gan, have invented certain new and usefulImprovements in Air and Steam Feeding Devices for Furnaces, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention consists in the peculiar construction of an air` and steam feeding device for furnaces; and it consists particularly in the construction of the various parts whereby an even distribution of the steam and air is obtained not only the whole length from front to rear of the grate, but also the whole width of the grate, thereby making more perfect combustion, economizing in fuel, and preventing the burning out of the grates at points where heretofore they have received an inadequate supply of air or steam, all as more fully hereinafter described.

In the drawings, Figure l is a vertical central section through a furnace, showing my invention applied thereto. Fig. 2 isa front elevation of the furnace, showing my invention applied thereto. Fig. 3 is a longitudinal section through one of the side walls. Fig.4= is an enlarged section through t-he air and steam supply pipes.

A is the steam-generator, beneath which is the furnace B, provided with the grates C. I prefer to use inclined grates, and have shown a construction embodying oppositely-inclined grates extending from the side walls D to at or near the middle of the furnace-chamber, where they are supported on a suitable pedestal E, this furnace being of well-known construction. In furnaces of this kind heretofore it has been customary to supply the draft for the combustion through the usual doors and dampers beneath the ash-pit at the front end. This produces a longitudinal draft through the furnace, which will create a much hotter fire at the rear of the furnace than at the forward end thereof, with much less perfect combustion at the front than the rear portion thereof. Where I employ the double inclined grates, as shown in the drawings, not only is the Afire greatest at the rear, but it is greatly increased at the bottom of the gratos, and so little air is drawn through the upper side portions thereof that the grates burn out more rapidly at their upper ends that at any other portion. It has also been proposed to inject air and steam at the front end of the furnace above the grates, but such construction has the objection that it produces a strong longitudinal draft and creates an uneven combustion over the gratesurface. By my construction these objections are overcome and a re is produced Awith even combustion in all parts of the grates and without danger of burning them out more 'rapidly in one place than in another.

In building new furnaces in which my improvement is to be applied I form in each side wall of the furnace beside the bottom of the grates a longitudinal air chamber E, which forms or in which is supported an airpipe F of a size to supply an abundance of air for the gratos. At its rear it is capped or supported in the bridge-Wall G to close that rear end, while its forward end is open and freely communicates with an air-chamber H in the front wall of the furnace within the boiler-front. In the boiler-front and opposite this air-chamber is a damper or valve I for controlling the amount of air to be admitted in to the chamber H.

J is a steam-supply pipe provided with a suitable controlling-valve K. This pipe at its lower end communicates into the jet-pipe L, which passes through the air-space I-I and through the air-pipe F, being supported free from the sides thereof, its rear end being closed. 'Ihe jet-pipe is provided with a series of horizontal apertures or jets M, arranged central-ly beside enlarged apertures N on the inner face of the air-pipe.

The parts being thus constructed and arranged, ,their operation is as follows: The re being started in a furnace of this kind and the ash-pit doors closed partially or entirely, the grates are properly covered with coal, the steam being turned on and the dampers I being partially opened to give the desired amount of air, the steam from the jets M'will be discharged through the apertures N and draw with it the air heated by the steam from the air-pipe, the mingled air and steam being discharged horizontally beneath the gratos the whole length thereof and at substantially right angles to the bed of fuel upon the gratos.

In practice the effect of this construction is to produce a fan-shaped blast of mingled air and steam, the lower limb of which is substantially horizontal, owing to the upward draft of the furnace, while the upper section will spread out over almost the entire Width of the grate, distributing the air and steam evenly over all parts, slightly more air and steam being discharged at the bottom of the inclined grates than at the top, and this is desirable as the hottest fire is at the lowest point. The shape of the blast is shown by the dotted lines in Fig. 1. Inasmuch as the ashpit chamber has no draft through it except that created by this air-feeding device, there is no longitudinal draft therein, so that there is no tendency for the air to be carried to the rear of the furnace until after it has passed through the grate. Thus I obtain an absolutely perfect distribution of the combustion, not only the whole length, but the Whole width of the grate-surface.

That I claim as my invention is l. The combination with the side walls and oppositely inclined grates of an air supply passage along or in the walls opposite the lower ends and beneath the upper ends of the grates having aseries of horizontal apertures therethrough, a valve controlling the end of said pipe located outside of the furnace and a steam pipe passing through the air pipe and having a series of discharge jets arranged opposite the apertures in the air pipe, substantially as described.

2. The combination in a frame, of oppositely inclined grates inclined from their upper ends downward toward the middle, air passages formed in the side walls opposite the lower end of the grates, air supply tubes in such passages, having a series of horizontal apertures on the inner face and their outer ends extending to the outside of the furnace, a damper controlling the outer end of the air pipe, a steam supply pipe passing centrally through the air pipe and having a series of jets smaller than the apertures in the air pipe, arranged centrally beside said apertures, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

THOMAS MURPHY. Witnesses:

M. B. ODOGHERTY, L. J. WHITTEMORE. 

